Hi Martin, You can set the threshold level with the “volume” command. I’m not familiar with “ccp4 style mask file” (and as far as I know Chimera doesn’t write mask files), but you can do the masking by the isosurface directly in Chimera with the “mask” command. Example: volume #0 level 0.02 mask #0 #0 model #1 That example has the trivial case of masking the volume by its own isosurface, but you can mask a map by the isosurface of some other map (or various surfaces created in different ways). The “volume” and “mask” commands have lots of options, see: <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/volume.html> <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/mask.html> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco
On Oct 20, 2017, at 7:30 AM, Martin Lawrence <lawrence@chemistry.montana.edu> wrote:
Hi All, Is there a quick and easy way in Chimera to impose a density level cutoff and write out a ccp4 style mask file? Thanks, Martin